Practice TEAS Science Test

Correct Answer: B

Rationale: The correct answer is B: Hypothalamus. The hypothalamus is responsible for maintaining homeostasis in the body by regulating various bodily functions such as body temperature, thirst, hunger, sleep, and hormonal balance. It receives input from different parts of the body and initiates responses to maintain internal stability. The brainstem (A) is involved in basic life functions like breathing and heart rate but does not play a direct role in homeostasis. The medulla oblongata (C) controls involuntary functions like breathing and swallowing. The cerebrum (D) is responsible for higher brain functions like thinking and voluntary movements, not for maintaining homeostasis.

Correct Answer: B

Rationale: The correct answer is B because the pericardium is actually a double-walled sac around the heart, not a single-walled layer. The outer layer is the fibrous pericardium, and the inner layer is the serous pericardium. Choice A is correct because the pericardial fluid between the layers reduces friction. Choice C is also correct because the pericardium helps prevent overfilling of the heart. Choice D is correct as well, as the pericardium does protect and anchor the heart. Therefore, the only incorrect statement is B, as the pericardium is not a single-walled layer.

Correct Answer: D

Rationale: The correct answer is D: Cardiovascular. The cardiovascular system is responsible for transporting dissolved oxygen from the lungs to the spleen. Step 1: Oxygen is inhaled into the lungs during respiration. Step 2: Oxygen diffuses into the bloodstream through the alveoli in the lungs. Step 3: The oxygen-rich blood is pumped by the heart to the spleen and other body tissues. The immune system (A) is responsible for fighting off infections, not oxygen transport. The endocrine system (B) regulates hormones, not oxygen transport. The respiratory system (C) is involved in the exchange of gases in the lungs but does not transport oxygen to the spleen.

Correct Answer: B

Rationale: The correct answer is B: Alveoli. Alveoli are tiny air sacs in the lungs where gas exchange occurs. Oxygen from the air we breathe passes into the blood vessels surrounding the alveoli, while carbon dioxide from the blood moves into the alveoli to be exhaled. The other choices are incorrect because: A: Trachea is the windpipe that carries air to and from the lungs, but gas exchange does not occur there. C: Bronchioles are small air passages that branch off the bronchi, leading air to the alveoli, but they are not the site of gas exchange. D: Diaphragm is a muscle that helps with breathing by expanding and contracting the chest cavity, but it is not directly involved in gas exchange.

Correct Answer: B

Rationale: The correct answer is B: Medulla oblongata. This part of the brain is located in the brainstem and is responsible for controlling vital involuntary functions like breathing, heart rate, and blood pressure. It contains nuclei that regulate these activities and plays a crucial role in maintaining homeostasis. The cerebellum (A) is involved in coordinating movement and balance, the cerebrum (C) is responsible for higher brain functions like thinking and decision-making, and the thalamus (D) acts as a relay center for sensory information. However, they are not directly involved in controlling involuntary actions like breathing and heart rate.